Typically, emergency signalling systems include a plurality of signalling devices. For example, a system may include a siren/speaker and primary and secondary visual indicators such as rotating and flashing lights and auxiliary lights such as take-down lights, alley lights and headlight flashers. Different combinations of these devices are simultaneously operated in order to create signalling schemes of different types. Each type is usually designed for use in a particular category of emergency situations. For example, when a vehicle incorporating the system is stopped on the side of a road in order to help a disabled vehicle, operation of only the flashing lights may be appropriate. When pursuing a vehicle, maximum signalling is required and the primary visual indicators (rotators) and a siren may be added to the flashing lights. A non-pursuit-type emergency may call for the primary visual indicators and the flashing lights, but no siren.
So the operator of the emergency vehicle does not have to configure his/her own emergency signalling each time the system is used, each system is typically designed to operate in one of a plurality of selectable "operating modes." Using the example of the previous paragraph, a first operating mode may operate the system with flashing lights only. A second operating mode may operate the flashing lights and the rotating lights. A third run mode may operate all of the flashing lights, rotating lights and the siren/speaker.
Designating the functions of each operating mode, however, restricts the versatility of the system and prevents an operator from tailoring the various operating modes to the needs of his/her particular application and environment. In order to provide some versatility to the system, it is known to provide dip switches on the circuit boards of the system that allow selected signalling features to be enabled for each operating mode. Unfortunately, the dip switches are not easily accessible and require a service technician to partially disassemble an installed system if the operating modes are to be changed. Moreover, they are expensive and require considerable space. In order to provide any significant amount of system versatility, a large number of the switches would be required, thereby making such a system bulky and expensive.